The superior temporal gyrus (STG) is important for hearing, language comprehension, learning, memory, recognition and semantic and phonological processing. Deficits of STG function are associated with pathological states (e.g., dyslexia, autism, schizophrenia). A quantitative characterization of the detailed anatomic structure of the STG is likely to be important in understanding both the normal function and pathological states related to its function as well as elucidate the differences between pathological groups. To conduct a thorough quantitative assessment of the STG, it is important to have a method capable of characterizing different parts of the STG reliably as well as analyzing shape and pattern characteristics. We propose the development and validation of such a method. Using conventional methods, we have already developed a highly reliable morphometric methodology to measure the STG and planum temporale (PT). Using that as a "gold standard," we propose to develop and validate semi-automated methods to measure these regions from a large population. Further, we will develop a shape analysis methodology to analyze the regions of the STG. Our lab currently has SGPR MRI scans on 30 schizophrenia patients individually matched with 30 normal subjects and 30 bipolar patients. We will use the above methods to investigate STG abnormalities in schizophrenia, This subject group provides an ideal starting point to validate semi-automated methods since schizophrenia patients have show STG cortical anomalies (e.g., reversed asymmetry of the PT) in morphometric studies. We believe the 30 bipolar patients are an important comparison group to the schizophrenia patients because it represents a psychiatric disorder that may have psychotic symptoms yet one in which there is no evidence of STG dysfunction. Defining differences in shape at specific locations of the STG and differences in gyral characteristics between patient groups and normal subjects may give important information about the etiology of schizophrenia, and aid in the differential diagnosis between schizophrenia and bipolar disorder.